Lock sliders for zippers



Jan; 4, 1966 .1. E. BURBANK 3,226,789

LOCK SLIDERS FOR ZIPPERS Filed Nov. 25, 1964 2 Sheets-Sheet 1 Fi .1.

n 4, 1966 J. E. BURBANK 3,226,189

LOCK SLIDERS FOR ZIPPERS 2 Sheets-Sheet 2 Filed Nov. 23, 1964 United States Patent 3,226,789 LOCK 'SLIDERS FOR ZIPPERS John E. Burbank, Middlebury, Conn., assignor to Scovlll Manufacturing Company, Waterbury, Conn., a corporation of Connecticut Filed Nov. 23, 1964, Ser. No. 412,898 Claims. (Cl. 24-20514) This invention relates to lock sliders for zipper fasteners of the plastic filament type, wherein the filament is usually in the form of a coil which is somewhat flattened and modified in shape to provide heads for interlocking with heads of another coil.

In prior lock sliders of one general type, a detent is forced or spring-pressed into one or more spaces between the fastener elements. Cam lock sliders have also been employed where locking is acomplished by pressure in a direction. perpendicular to the plane of the zipper. In either case, these are certain disadvantages, particularly in locking sliders on zippers of the plastic filament type,

wherein the individual fastener elements are not as strong as metal elements and are moreeasily damaged.

An object of this invention, therefore, is to provide an improved lock slider for zippers of the plastic filament type which will overcome the drawbacks to sliders.

With plastic coil fasteners, in addition to the fact that prior lock the material is relatively soft and flexible, no single convolution is rigidly attached to the tape. The slider of my invention provides a gripping or binding effect on a plurality of such convolutions of both coils, which convolutions derive mutual support from each other and from adjacent portions of the fastener.

In accordance with the invention, a plurality of sidewise acting cams or the like, are provided on the pull tab, and these cams are so constructed and arranged that they will grip around the outer ends of the plastic filament elements thereby causing the chain to jam together and constrict their passage through the Y-shaped branches of the slider channel. In other words, the individual elements are constrained so that they will abut against the slider neck to prevent their exit from the slider in a more positive way, than mere reliance on friction.

Another object of the invention is to provide an improved lock slider especially for coil type zippers, which is adaptable for a double or a reversible lock, where there is a pull tab on each side of the slider adapted for alternate use as in reversible coats.

A still further object of the invention is to provide a lock .sliderwherein the locking projections or cams on the pull tab supported against sidewise deformation when in locked position by the flanges of the slider.

Other objects and advantages of the invention will hereinafter more fully appear. a

In the drawing, I have shown for purposes of illustration, one embodiment which the invention may assume in practice. In the drawings:

FIG. 1 is a front view of a zipper of the plastic filament type for which my invention is especially suited;

FIG. 2 is also a front view on an enlarged scale with the top of the slider removed and with the elements shown in their normal unlocked position;

FIG. 3 is a view similar to FIG. 2 except that the elements are shown in their locked position and the locking cam in horizontal section;

FIG. 4 is a bottom plan view of the pull tab with its locking cams;

FIG. 5 is an end view of the pull tab;

FIG. 6 is a vertical cross-section on line-6-6 of FIG. 3;

FIG. 7 is a vertical longitudinal section on line 77 of FIG. 6;

FIG. 8 is a view similar to FIG. 3 showing a modified shape of the locking cams;

FIG. 9 is a vertical section similar to FIG. 7 showing the invention as embodied in a double pull or reversible type zipper; and

FIG. 10 is a perspective view of another shape of cam.

The zipper fastener illustrated in the drawing has a pair of fastener elements 11 and 12 of the plastic filament type, each of which is in the shape of a flattened coil with spaced convolutions, each convolution having a head end 13 adapted to interlock between a pair of convolutions of the mating coil and a heel end 14 which as seen in FIG. 6, is of rounded shape transversely of the fastener.

The usual form of end stops may be provided. The top portion of the fastener is not shown, but there is indicated in FIG. 1 a separable bottom stop 15.

The slider body is of a common type having a front Wing 16 and a back wing 17. Either or both of these wings may be provided with side flanges and as herein shown, the front wing has comparatively deep uninterrupted flanges 18 while the back wing has only shallow flanges 19. The front and back wings are united at their wider ends by an integral neck 20. Thus, the wings, neck and flanges form a slider channel with a pair of divergent upper branches merging into or joining a single lower branch.

The pull tab 21 has spaced arms 22 and 23 with trunnions 24 extending into a recessed lug 25 on the front wing to form a pivotal mounting for the pull tab. The front wing has apertures 26 and 27 on opposite sides of the pivotal mounting and the outer edges of these apertures are preferably in alignment with the inner surfaces of the guide flanges 18 at the juncture of the branches of the slider channel.

Along the lateral edges of the pull tab at its hinged end are slider locking cams 28 and 29. These cams extend from the free end of the tab which is slightly beyond the pivotal axis, along the length of the pull tab for a substantial distance. While the outer sides of the cams are vertical, their inner sides are relieved as indicated at 30 and 31, so that they have relatively thick and deep portions 32 in the region of the pivotal axis and taper away from the thicker and deeper portions.

The cams 28 and 29 are aligned with the apertures 26 and 27, respectively, so that when the pull tab is swung down against the slider, the cam will wedge over the heel ends 14 of the fastening elements and squeeze the coil convolutions inwardly toward each other. In this action and while in locked position, the cams are supported against sidewise stress by the flanges 18. When in locked position the coils inside the slide assume some such position as shown in FIG. 3. Here the upper branches of the channel are constricted between the thicker portions 32 of the cams and the slider neck 20. Furthermore, one or more of the head ends 13 of the coil convolutions will lodge under the slider neck as seen in FIG. 3 to provide a more positive locking.

In FIG. 8, there is shown a slightly modified form of cam in which the inside faces do not taper smoothly from the side and to the thin end, but may have one or more bumps or projections 33 on their inner surfaces. These would be intended to project slightly into the spaces between the heel ends of the fastening elements.

In FIG. 10, the cam is shown as having irregularities in the form of ridges 34 which may extend across the bottom edge of the cam and the inner side surfaces. Any such irregularities or roughening of these surfaces, especially in the region of the pivot, will assist in dragging or. pulling the tab into locked position after its initial engagement with the fastening elements whenever a sidewise pull is placed npon the zipper.

The invention is shown as embodied in a reversible lock slider in FIG. 9. Here, there are two pull tabs 35 and 36 pivoted to the front and back wings with the pivotal axes being opposite one another. In this case, the cams preferably have some such configuration as those shown in FIG. 10 and both the cam 37 on the pull tab 35 and the cam 38 on the pull tab 36 are constructed so that they will leave a small space indicated at 39 to accommodate the zipper tape which is designated 40 in FIGS. 1, 2, 3, 6 and 8. Preferably, both cams are alike and thus neither of them will extend half way around the heel ends of the fastening elements.

What I claim is:

1. In a zipper fastener, a pair of fastening elements of the plastic filament type, each of which is in the shape of a flattened coil with spaced convolutions, each convolution having a head end adapted to interlock between a pair of convolutions of the mating coil and a heel end of rounded shape transversely of the fastener,

a slider having front and back wings, a neck uniting said wings at one end, uninterrupted guide flanges at the lateral edges of at least one of said wings, which guide flanges ride over said heel ends of the coils, said wings, neck and flanges forming a slider channel wih a pair of divergent upper branches joining a single lower branch, a rectangular pull tab having spaced apart arms pivotally mounted on said front wing, said front wing having apertures on opposite sides of the pull tab pivotal mounting, the outer edges of said apertures being substantially in alignment with said guide flanges at the juncture of said channel branches, and

a pair of slider locking cams projecting inwardly from said arms along the side edges of said pull tab, said cams extending through said apertures into the slider channel when the pull tab is swung down into locked position, said cams when in locked position being supported against outward lateral deformation by slider wing material alongside said apertures, each of said cams having a relatively thick and deep portion in the region of the pivot axis, the inner or opposed faces of said cams being relieved both vertically and horizontally of the pull tab so that each cam is generally tapering in both directions away from said relatively thick portion, whereby in locked position the cams will wedge over the heel ends of a plurality of coil convolutions of each coil, said relatively thick and deep portions of the cams serving to force the pull tab into locking position when a tearing stress is applied to the zipper in the region of the slider, after initial engagement of such portions with one or more coil convolutions.

2. In a zipper fastener the combination as defined in claim 1, wherein the upper ends or relatively thick and deep portions of said cams, when in locked position, extend a substantial distance into said diverging branches of the slider channels, whereby the coil convolutions adjacent said slider neck will be forced laterally inwardly to a sufficient extent to cause jamming of the head ends of at least one of the coil convolutions under the neck of the slider.

3. In a zipper fastener, the combination defined in claim 1, wherein said cams in locked position extend around at least half of the heel ends of a plurality of coil convolutions.

4. In a zipper fastener the combination defined in claim 1, wherein portions of the coil engaging surfaces of said cams are irregular or roughened to assist the cam being self-propelled into locked position once the cams have made initial contact with the fastening elements.

5. In a zipper fastener the combination as defined in claim 1, together with a second pull tab similar to that on the front wing is mounted in a like way to the back wing, the back wing being apertured like the front wing, wherein the cams on both pull tabs are shaped as defined in claim 1, but which in locked position leave a space between the front and back cams sufllcient to accommodate the tapes on which the coils are anchored.

2/ 1961 Burbank. 1/ 1962 Huelster.

WILLIAM FELDMAN, Primary Examiner. 

1. IN A ZIPPER FASTENER, A PAIR OF FASTENING ELEMENTS OF THE PLASTIC FILAMENT TYPE, EACH OF WHICH IS IN THE SHAPE OF A FLATTENED COIL WITH SPACED CONVOLUTIONS, EACH CONVOLUTION HAVING A HEAD END ADAPTED TO INTERLOCK BETWEEN A PAIR OF CONVOLUTIONS OF THE MATING COIL AND A HEEL END OF ROUNDED SHAPE TRANSVERSELY OF THE FASTENER, A SLIDER HAVING FRONT AND BACK WINGS, A NECK UNITING SAID WINGS AT ONE END, UNINTERRUPTED GUIDE FLANGES, AT THE LATERAL EDGES OF AT LEAST ONE OF SAID WINGS, WHICH GUIDE FLANGES RIDE OVER SAID HEEL ENDS OF THE COILS, SAID WINGS, NECK AND FLANGES FORMING A SLIDER CHANNEL WITH A PAIR OF DIVERGENT UPPER BRANCHES JOINING A SINGLE LOWER BRANCH, A RECTANGULAR PULL TAB HAVING SPACED APART ARMS PIVOTALLY MOUNTED ON SAID FRONT WING, SAID FRONT WING HAVING APERTURES ON OPPOSITE SIDES OF THE PULL TAB PIVOTAL MOUNTING, THE OUTER EDGES OF SAID APERTURES BEING SUBSTANTIALLY IN ALIGNMENT WITH SAID GUIDE FLANGES AT THE JUNCTURE OF SAID CHANNEL BRANCHES, AND A PAIR OF SLIDER LOCKING CAMS PROJECTING INWARDLY FROM SAID ARMS ALONG THE SIDE EDGES OF SAID PULL TAB, SAID CAMS EXTENDING THROUGH SAID APERTURES INTO THE SLIDER CHANNEL WHEN THE PULL TAB IS SWUNG DOWN INTO LOCKED POSITION, SAID CAMS WHEN IN LOCKED POSITION BEING SUPPORTED AGAINST OUTWARD LATERAL DEFORMATION BY SLIDER WING MATERIAL ALONGSIDE SAID APERTURES, EACH OF SAID CAMS HAVING A RELATIVELY THICK AND DEEP PORTION IN THE REGION OF THE PIVOT AXIS, THE INNER OR OPPOSED FACES OF SAID CAMS BEING RELIEVED BOTH VERTICALLY AND HORIZONTALLY OF THE PULL TAB SO THAT EACH CAM IS GENERALLY TAPERING IN BOTH DIRECTIONS AWAY FROM SAID RELATIVELY THICK PORTION, WHEREBY IN LOCKED POSITION THE CAM WILL WEDGE OVER THE HEEL ENDS OF A PLURALITY OF COIL CONVOLUTIONS OF EACH COIL, SAID RELATIVELY THICK AND DEEP PORTIONS OF THE CAMS SERVING TO FORCE THE PULL TAB INTO LOCKING POSITION WHEN A TEARING STRESS IS APPLIED TO THE ZIPPER IN THE REGION OF THE SLIDER, AFTER INITIAL ENGAGEMENT OF SUCH PORTIONS WITH ONE OR MORE COIL CONVOLUTIONS. 